Implantable active medical devices, such as cardiac rhythm management devices (pacemakers and defibrillators) and a variety of implantable muscle/nerve stimulators generally include a battery and battery-powered electronic pulse generator contained within a hermetically sealed housing or case and attached to a lead connector housing or lead connector block. The lead connector block is often affixed to the hermetically sealed housing with brackets, metal solder, and/or a medical grade adhesive.
The electronics within the hermetically sealed housing are conductively coupled to the lead connector block with an electrical feedthrough assembly. Electrical feedthroughs serve the purpose of providing a conductive path extending between the interior of a hermetically sealed container and a point outside the hermetically sealed housing. The conductive path through the feedthrough usually includes a conductor pin or terminal that is electrically insulated from the hermetically sealed housing. Many such feedthroughs are known in the art that provide the conductive path and seal the electrical container from its ambient environment. Such feedthroughs typically include a ferrule, and an insulative material such as a hermetic glass or ceramic seal that positions and insulates the pin within the ferrule. Sometimes it is desired that the electrical device include a capacitor within the ferrule and around the terminal, thus shunting any electromagnetic interference (EMI) at high frequencies at the entrance to the electrical device to which the feedthrough device is attached. Typically, the capacitor electrically contacts the pin lead and the ferrule. While this arrangement has proven to be highly reliable, it involves a variety of expensive manufacturing processes and parts that necessarily increase the cost of the resulting product.
Ongoing efforts by the industry to reduce the size of the implantable device are desired. Early implantable pacemakers back in the 1960's were about the size of a hockey puck. With advances in microelectronics and integrated circuitry, significantly more features and capabilities have been embodied in implantable active medical devices capable of sizes as small as about 10 cc. Nonetheless, efforts to further reduce the size of implantable active medical devices continue in the industry.